Comedians once embraced a signature quip or look, so why have such tropes fallen out of favour? Related: Stand down: when comics make unfunny big-screen comedies Imagine a museum devoted to the iconography of comedy. There would be glass cases containing Del Boy's flat cap, Father Ted's dog collar and a perfectly preserved set of fork handles. There'd be an animatronic mannequin of Basil Fawlty, performing his impres…